1. The Field of the Invention
The present invention is in the field of compositions and devices used to deliver a medicament to a person's teeth and/or gingiva. More particularly, the invention relates to medicament compositions in the shape of a dental tray, and devices that utilize such compositions, that become adhesive when moistened (e.g., by saliva in a user's mouth), as well as methods for their manufacture and use.
2. The Relevant Technology
Bacterial infections or other oral tissue irritants are a common problem for many dental patients. Such infections and/or irritants may be caused from or be associated with inflammation, bleeding, plaque accumulation, calculus (tartar) accumulation, bad breath, gingivitis, periodontitis, cavities, abscesses, canker sores, cold sores, pustulas, etc. Such bacterial infections/irritants can become so uncomfortable that it may prevent a patient from eating or drinking certain foods, socializing, or maintaining good oral hygiene practices.
To relieve and treat bacterial infections and/or oral tissue irritants, there are currently many non-permanent treatment options available. The most common options include using medicament toothpastes, varnishes, gels, and rinses. These products may include, but are not limited to, medicaments such as chlorhexidine gluconate, cetylpyridinium chloride, phenol, minocycline, tetracycline, doxycycline, penicillin, clindamycin, ciprofloxacin, metronidazole, and tricolsan.
Medicament dentifrices are a popular treatment option in treating bacterial infections and/or oral irritants. To use medicament dentifrices, it is usually recommended that the patient use the dentifrice twice daily. However, results are not immediate. It usually takes an extended period of time (about 1–4 weeks) to see any results from the medicament dentifrice. The main reason for this is that people typically only brush their teeth for about 60 seconds or less, which translates into extremely limited contact time between the medicament and the person's teeth and/or gingiva.
Another common treatment option involves the use of medicament rinses. To use medicament rinses, a patient usually “swishes” the rinse within their mouth several times per day. However, rinses only temporarily remain on oral surfaces and are only capable of providing momentary exposure to the medicament due to common movements of the patient's mouth, jaw, and tongue.
Medicament gels may also be used to treat bacterial infections and/or oral irritants and can be applied using custom-fitted trays. The process of making a custom-fitted tray generally involves: (1) making an alginate impression of the patient's teeth; (2) making a stone cast or model of the impression; (3) vacuum forming a dental tray from the model, usually from a heated sheet of thin ethyl vinyl acetate (EVA) material, and (4) trimming to allow for the desired amount of gingival coverage. This method results in a tray that is soft and flexible, that is customized to very accurately fit over the patient's teeth and gingiva, and that is therefore very comfortable to wear. In sum, the process for making a customized tray is time consuming, often taking days or weeks before the customized tray is available to the patient, and the resulting tray can be expensive.
Because of the time and cost associated with customized trays, less time consuming and costly alternatives have been developed. One alternative to customized dental trays is non-customized trays that approximate the shapes and sizes of a variety of users' dental arches. While non-customized dental trays can be used without the need for a professional customization procedure by a dentist, such trays tend to be more bulky and less comfortable than custom-fitted trays. Dental trays that can be self-customized (e.g., so-called “boil and bite” trays) are somewhat more comfortable and better-fitting compared to non-custom trays but less comfortable than trays that are customized by a dentist.
An alternative to the use of dental trays involves placing a flexible dental treatment strip over a user's teeth and/or gingival surfaces, typically for bleaching. Dental strips typically comprise a flexible plastic strip coated with a moist dental gel on the side of the strip facing the user's teeth and gingiva. To install the strip, a portion of the strip is first placed over the front surfaces of the user's teeth and/or gingiva, followed by folding the remainder of the strip around the occlusal edges of the teeth and back against a portion of the lingual surfaces of the teeth and gingiva. Like paint-on bleaching compositions, the use of dental strips does not require the user to use a customized or non-customized tray. An advantage of dental strips over paint-on compositions is that strips include a barrier that, at least in theory, protects the moist gel composition from diffusing into the user's mouth.
In reality, because of the generally poor adhesion of dental strips to the user's teeth and gingiva, coupled with their generally flimsy nature, it is often difficult for the user to maintain the strips in their proper position. Dental strips are prone to slip off the teeth and/or gingiva through even minimal movement of the user's mouth, jaw or tongue. Indeed, it is recommended that the user not eat, drink, smoke or sleep while wearing dental strips.
Even if a user successfully maintains the strip in its proper position during the entire treatment time, the flowable gel composition can diffuse into the person's saliva, potentially causing a poor taste in the user's mouth and possibly discomfort to soft oral and throat tissues. The tendency of the gel to diffuse into the user's mouth can be accelerated through even minimal shifts of the dental strip over the user's teeth/gingiva, with each shift potentially exposing a new portion of the gel that remains adhered to the newly exposed surface of the user's teeth/gingiva. In some cases, the dental strip can become so dislodged or mangled that it must be removed by the user and replaced with a fresh strip to complete the recommended treatment time. This multiplies the cost and hassle of the dental strip method.
In practical terms, the use of dental strips can greatly inhibit even the simplest of activities that involve movement of the user's mouth or tongue, such as talking, coughing, yawning, smiling, making other facial expressions, or even swallowing (which normally occurs subconsciously throughout the day). Indeed, the time when a person's mouth and tongue are prone to move the least is at night while the person is sleeping. Unfortunately, it is recommended that dental strips not be used while sleeping, presumably to prevent accidental choking on an inadvertently dislodged strip. This only confirms the tendency of conventional dental strips to easily dislodge from a user's teeth and/or gingiva.
In view of the foregoing, there is an ongoing need for improved medicament compositions, apparatus and methods that are simple and easy to use, that more reliably remain in position over a user's teeth and/or gingiva, and that result in less diffusion of medicament compositions into a user's oral cavity. Such improvements would be expected to improve or encourage compliance by the user.